Response of cave invertebrate communities to habitat heterogeneity at different scales

Abstract

This dissertation was developed with the aim of evaluating the influence of habitat heterogeneity, measured through physical, trophic and microclimatic attributes of the cave floor on the composition and richness of cave invertebrates at different sample scales. The study site was Serra do Ramalho, in Western Bahia, and comprises 26 caves spread over an area of approximately 2.300 km2. The results showed here can contribute not only to the Ecology of communities, but also to the conservation of cave invertebrate fauna in Brazil. The dissertation is composed of two manuscripts written according to the norms of two different scientific journals. The first was written according to the rules of the journal ―Biodiversity and conservation‖, whose objective was to evaluate local and regional attributes that determine the composition and richness of cave invertebrates. Locally, we collected in 26 caves and evaluated the influence of trophic, physical and microclimatic attributes on the troglobitic and non-troglobitic fauna. Regionally, we evaluated the influence of drainage basins and water discharge and recharge zones on the composition of troglobitic and non-troglobitic fauna. The results show that variables related to trophic attributes, microclimate and physical attributes of the cave substrate together and/or separately influence the structure of cave communities. In addition, the scale proved to be an important factor in detecting community responses. At the landscape level, the only variable that influences the composition of the cave fauna was the water recharge and discharge zone. The second manuscript was written according to the norms of the journal ―Acta Oecologica‖, and had as main objective to evaluate the role of the distance of the entrances in the determination of variations in the characteristics of the microhabitats, in the composition and richness of the fauna of troglobitic and non- troglobitic. For this work, we used Três Cobras Cave, which has seven entrances and more than five thousand meters of linear development. The results showed that distance from the entrance affects the conditions and resources throughout the cave and consequently, creates distinct microhabitats and determines variations in the composition and richness of the troglobitic fauna.